Manufacturers and distributors of retail products generally monitor product sales in order to maintain proper inventory and to direct marketing efforts. Monitoring may be done by sampling sales at retail outlets and transferring sales data to a central point for evaluation. Retail outlets usually cooperate in providing sales data but a significant number of retail outlets are not able to or do not elect to have sales data sampled in a form needed for analysis. As a result, it is necessary to estimate product sales of unsampled and poorly sampled individual outlets to provide marketing information.
In some industries, distribution of certain products is controlled so that additional data relating to the control of such products is needed for marketing purposes. In the pharmaceutical industry, for example, many products are sold by prescription and such sales are controlled by prescribing physicians. As a result, it is desirable to determine the number of prescriptions written by a physician so that marketing efforts may be directed to the prescribing physicians.
Estimates of business sales in small areas, such as counties of a state, have been made on the basis of known data for the state under the assumption that the relationships for the state also hold for the county. The article “Small-Area Estimation of Economic Statistics” by Cary T. Isaki, Journal of Business and Economic Statistics, Vol. D, No. 4, October, 1990, pages 435–441 describes a ratio correlation (multiple regression) approach for estimating retail sales for small areas (counties) using county-to-state shares of retail sales from two successive economic censuses. While these methods provide estimates of retail sales over a relatively small county area from publicly available data, they are not adapted to estimate retail sales of individual outlets where individual outlet characteristics differ widely. As a result, the estimates for individual outlets based on wide area data are biased and may not reflect actual sales of an individual outlet.
Estimation of physician prescribing activity has been attempted by marketing research practitioners based on ratio estimators and inflation factor estimators as commonly described in such texts as “Sampling Techniques” by W. G. Cochran, John Wiley, New York 1977. These methods attempt to estimate the activity in a pre-established geographic area of known dimensions by scaling up a sample of activity within the area in proportion to the level of a known auxiliary variable (i.e., ratio estimate) or in proportion to the level of sample coverage (via an inflation factor) for the entire area. Typical geographic areas encompass a number of outlets and prescribers. Such geographic-based methods do not yield estimates of each individual prescriber's activity within each individual outlet but only produce a measure of the total activity for the geography. If prescriber level estimates are desired, these methods must assume that the proportion of the total activity that is captured in the sample data (i.e., the captured proportion) of each prescriber is the same. If outlet estimates are desired, it must then be assumed that each unsampled outlet is accurately represented by the average of the sampled outlets in the geography. With these assumptions, all sample data within a stratum receive the same “scale-up” factor. These assumptions, however, are known to be false and result in biased estimates at the activity source level.
U.S. Pat. No. 5,781,893 discloses systems and methods for estimating sales activity of a product at sales outlets including sales outlets at which sales activity data is sampled and unsampled is estimated by determining the distances between each of the sampled sales outlets and each of the unsampled sales outlets and correlating sales activity data from the sampled sales outlets according to the determined distances. The sales activity volume of the product at the sampled outlets and the estimated sales activity volume of the product at the unsampled outlets are combined to obtain an estimate of sales activity for all the sales outlets. Sales activity of products prescribed by a physician at both the sampled and unsampled outlets can be estimated by correlating sales activity data for the prescribing physician at the sampled outlets according to the distances between the sampled outlets and the unsampled outlets. The systems and methods of the '893 patent provide reliable estimates of product distribution when the product has a broad usage base that lends itself to continuous geo-spatial assumptions regarding such product sales. However, in the context of specialty markets, which are defined as products used by specialized consuming populations (e.g., HIV drugs) or products which otherwise require special handling (e.g., such as refrigeration), many assumptions established for broad market estimation are inapplicable. Accordingly, there remains a need to provide a system and method for providing reliable estimates from product sales and distribution in specialty markets.